Is Investing $50 a Month Worth It? The Real Numbers

That $8 is an assumption, set below the S&P 500’s long-run average of about $10 a year per $100 since 1957. Markets don’t move in a straight line: in 2008, $100 in the S&P 500 fell to about $63. Over a few years, $50 a month can be worth less than you put in.

Illustrative only: 8% assumed annual return, set below the S&P 500's long-run average of about 10% since 1957. Not a forecast or a guarantee. Real results will differ and you can lose money.

Look at the last two rows. Between year 20 and year 30, the balance grows by about $45,000, and only $6,000 of that is new deposits. The rest is growth on growth, and it needs years more than it needs dollars.

It’s also why $50 now can beat $100 later. On the same assumption, wait ten years and invest $100 a month for 20 years instead, and you’d come to about $58,900. You’d have put in $6,000 more and ended with less.

A fee that looks small takes a big bite out of a small deposit. A $3 monthly account fee on a $50 deposit takes $6 of every $100 before the market does anything.

In October 2019, Schwab cut commissions on online U.S. stock and ETF trades to zero, and TD Ameritrade and E*Trade matched within days. Check two things before you start: that your broker doesn’t charge to trade or to hold the account, and what the fund itself costs each year, which is listed as its expense ratio. Coinage’s free plan has no subscription fee, and Coinage charges no other platform fees; your broker’s own fees, if any, still apply.

A single share of a big index fund can cost hundreds of dollars. With fractional shares, $50 buys a slice of one. Many brokers offer them; check that yours does for the fund you want.

At $50 a month, ten holdings would mean $5 each. A broad index fund already owns hundreds of companies in one purchase. A single stock puts all $50 on one.

Coinage’s Maxi mode is built around one pick. You choose one stock or ETF, and the buying you do through Coinage goes into it: a recurring buy you set every week, every two weeks or every month, plus any of your rules you move over. Pick a broad index fund and each $50 is spread across hundreds of companies at once. Maxi is free. You can turn it off any time, and turning it off sells nothing. Maxi is open to eligible U.S. users with a supported broker, and your broker needs to support fractional shares of the fund you pick.

Double it to $100 and the 30-year figure roughly doubles too, to about $149,000. One option is to raise it a little each time your pay goes up.

Spend Matching can add a little more without a decision. Move a rule to your Maxi pick, and a small match on something you buy anyway, like $1 on every coffee, adds up and buys into it once the total is big enough, using cash in your investing account.

If you carry a credit card balance, paying it down usually comes first. Card accounts that were charged interest paid about $22 a year per $100 in August, far more than the $8 assumption here. And if you have no cushion for surprises, build one in a high-yield savings account first, so a bad month doesn’t force you to sell after a drop.

Fifty dollars won’t change your next year. Its job is to get the clock started, because the clock is what does most of the work.